According to the state of the art, structural components that are to be connected together in a manner that is selectively rigid or flexibly movable are typically connected by a joint or hinge structure that is, in itself, flexible. In order to provide the necessary rigidity in addition to the necessary flexibility, the known structures further include a locking device that can be selectively locked or released, so as to selectively lock the flexible joint in one or more desired fixed positions, or alternatively release the joint to allow it to be flexibly bendable. The selective operation of the locking device further requires the use of a control unit for actuating the locking device. As a result, known load carrying structures that are selectively adjustable to be rigid or flexible thus require complicated joint members and locking devices, and a rather great total number of components interacting in rather complicated ways. This is especially disadvantageous in structures that are to be built according to lightweight construction techniques, for which the primary goal is naturally a minimization of the overall weight together with a reduction of the number of components.